1. Field of the Invention
The invention relates to an aqueous liquid bleaching composition comprising a solid, substantially water insoluble organic peroxy acid, which composition may be used for the treatment of fabrics and hard surfaces.
2. The Prior Art
Suspending agents for solid, substantially water insoluble organic peroxy acids in aqueous media have been reported in a number of patents.
U.S. Pat. No. 3,996,152 (Edwards et al.) discloses use of non-starch thickening agents such as Carbopol 940.RTM. to suspend bleaches such as diperazelaic acid at low pH in aqueous media. Starch thickening agents were found useful in similar systems as reported in U.S. Pat. No. 4,017,412 (Bradley). Thickening agents of the aforementioned types form gel-like systems which upon storage at elevated temperatures exhibit instability problems. When used at higher levels, these thickeners are more stable but now cause difficulties with pourability.
U.S. Pat. No. 4,642,198 (Humphreys et al.) reports a further advance in this technology by the use of surfactants as structurants. A wide variety of detergents including anionics, nonionics and mixtures thereof were reported as effective. Among the nonionics listed were alkoxylated condensation products of alcohols, of alkyl phenols, of fatty acids and of fatty acid amides. According to the examples, there is particularly preferred combinations of sodium alkylbenzene sulfonate and C.sub.12 -C.sub.15 primary alcohols condensed with 7 moles ethylene oxide.
EP No. 0 176 124 (DeJong et al.) reports similar low pH aqueous suspensions of peroxy carboxylic acids. This art informs that surfactants other than alkylbenzene sulfonate have a detrimental effect upon chemical stability of the peroxy carboxylic acid containing suspensions. Experimental data therein shows a number of well-known detergents causing suspension destabilization. These destabilizing detergents include lauryl sulfate, C.sub.15 alkyl ether sulfate, ethoxylated nonyl phenol, ethylene oxide/propylene oxide copolymer and secondary alkane sulfonate.
EP No. 0 240 481 (Boyer et al.) seemingly also finds some special significance in the use of alkylbenzene sulfonate and suggests that the structured diperoxy acid bleach suspensions be substantially free of other surfactants. The patent then discloses a cleaning procedure whereby a first composition of the low pH surfactant structured 1,12-diperoxydodecanedioic acid can be used in a combination with a second high pH cleaning liquid containing further surfactants, enzyme and evidently neutralized C.sub.12 -C.sub.14 fatty acid.
U.S. Pat. No. 4,655,781 (Hsieh et al.) reports the structuring of surface active peroxy acids in substantially non-aqueous media at pH 7 to 12. Surfactants experimentally investigated included linear alkylbenzene sulfonate, fatty acids and sodium alkyl sulfate.
A problem which has been noted with all the foregoing systems is that while chemical and physical stability may have been improved within the lower temperature range, there still remain instability problems at slightly elevated temperatures.
Consequently, it is an object of the present invention to provide an improved aqueous liquid bleach composition comprising a solid, substantially water-insoluble organic peroxy acid wherein the above drawbacks are mitigated.
More specifically, it is an object of the present invention to provide an aqueous suspension of a solid, substantially water-insoluble organic peroxy acid which is chemically and physically storage stable throughout a wide range of temperatures.
These and other objects of the present invention will become apparent as further details are provided in the subsequent discussion and Examples.